sam000lee
Forum Mentor
Chiming in with others, the NGK B8ES is the correct plug. I live in Boston and depending on when I need them, sometimes end up having to go to 3-4 part stores to get a set of four. I'll typically just buy all the ones they have for spares. You should also be able to get them on z1. As for the oil filter, the correct K&N filter is the KN133. $8 or $9 on amazon and I'll also typically just buy a few at a time. Between me and my friends we have 6-8 GS's so it helps to have extras 
. Honestly at this point I just buy multiple of everything and then charge them when I inevitably end up replacing stuff.
The petcock has three positions:
ON: Lever pointing down. Vacuum operated.
RES: Lever pointing left. Vacuum operated.
PRI: Lever pointing right. NOT vacuum operated and pulls from the "reserve level" (i.e. bottom of the tank)
If your bike is only running in the Prime position then there's an issue with your vacuum line or the petcock itself. Check to make sure that there are two lines hooked up to the petcock. If only the fuel line is connected, the ON position wouldn't work and you'll also likely have a huge vacuum leak going into the carbs from the line that should be connected to the petcock (this could certainly cause/contribute to the symptoms you're seeing and also potentially cause engine damage).
As for the two throttle cables, your GS550 has a push and a pull cable. Your pull cable is the one that opens the carb slides so is almost certainly the one that is still connected. Just hook the other one back up. Better yet, pull the carbs and rebuild them and then hook everything up correctly.
For your benefit and to make it easier for us to help you, I'd recommend you create a flickr account so that you can post pictures inline.
I'm mostly done with my GS550 resto. I bought it for $900 and have spent about the same to get it to a point where it runs well, behaves well (suspension), and is safe (tires and brakes). I've brought back a few of these bikes at this point - it feels like a lot to spend up front but ends up being cheaper than doing things multiple times.
. Honestly at this point I just buy multiple of everything and then charge them when I inevitably end up replacing stuff.The petcock has three positions:
ON: Lever pointing down. Vacuum operated.
RES: Lever pointing left. Vacuum operated.
PRI: Lever pointing right. NOT vacuum operated and pulls from the "reserve level" (i.e. bottom of the tank)
If your bike is only running in the Prime position then there's an issue with your vacuum line or the petcock itself. Check to make sure that there are two lines hooked up to the petcock. If only the fuel line is connected, the ON position wouldn't work and you'll also likely have a huge vacuum leak going into the carbs from the line that should be connected to the petcock (this could certainly cause/contribute to the symptoms you're seeing and also potentially cause engine damage).
As for the two throttle cables, your GS550 has a push and a pull cable. Your pull cable is the one that opens the carb slides so is almost certainly the one that is still connected. Just hook the other one back up. Better yet, pull the carbs and rebuild them and then hook everything up correctly.
For your benefit and to make it easier for us to help you, I'd recommend you create a flickr account so that you can post pictures inline.
I'm mostly done with my GS550 resto. I bought it for $900 and have spent about the same to get it to a point where it runs well, behaves well (suspension), and is safe (tires and brakes). I've brought back a few of these bikes at this point - it feels like a lot to spend up front but ends up being cheaper than doing things multiple times.
